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Inside the numbers: Don’t let the numbers overwhelm when buying a bull

by Wyoming Livestock Roundup

With the amount of bull data available, it can be easy for ranchers to become overwhelmed when they attend a bull sale. Travis Taylor, Colorado State University Extension specialist, has some advice for producers.

“Ranchers should do their homework before they attend the bull sale. Go to the bull sale with herd improvement goals in mind. We need to know what we want to change and have our goals laid out,” he told producers during a recent beef profitability meeting.

“Going to a bull sale without herd improvement goals is like shopping the supermarket hungry,” he continued. “Analyze the records that are available beforehand. We don’t want to buy the Snickers bar that only satisfies us one breeding season.”

In addition to looking at value indexes and EPDs, producers will still want to look at the visual appeal of the bull. Soundness and scrotal circumference are still important.

“We want to remember that 75 percent of the genetics in our herd is a result of the past two generations of sire selection,” he said.

Physical values

Taylor told producers that scrotal and udder scores are hard, tangible values that producers don’t always remember to look at. He shared a story about purchasing a bull with tremendous performance numbers and high dollar value.

“This bull produced fantastic calves, and a large number of heifers were retained. Within three years, most of those heifers were out of the herd because of their udders. They really fell apart. That is why it is important to look at the numbers to avoid some of these downfalls,” he said.

Beef Improvement recommends bulls have a scrotal circumference that is a minimum of 30 centimeters just to pass a breeding soundness exam. Terminal sires should have a scrotal circumference of 32 centimeters and maternal sires 34 centimeters.

“What ranchers need to find out when they are looking at a bull, is if the scrotal circumference score listed is actual or adjusted,” Taylor said.

If a 10-month old bull is adjusted to 34 centimeters, will he actually become 34 centimeters? If he is actually less than that, he may not settle as many cows as he should, Taylor added.

“When we visit with a producer, it is important to understand what the numbers they provide actually mean,” he commented.


Bull customers can be bombarded with EPDs, pedigrees and phenotypic data to calculate heritability estimates. However, the accuracy of these numbers is also important. Taylor said a young, unproven bull will have an accuracy of 0.05, although he may have 0.18 if he has proven ancestors.

What this means is, if a bull has an average weaning weight of 500 pounds, his offspring could range from 450 to 550 pounds on an average accuracy bull. As the bull has more offspring, the producer will get a truer measurement of what that bull is capable of producing.

“It is important to pay attention to accuracies to eliminate some of the variation in a bull,” Taylor said. “When buying a bull, remember the calf has a mother, so some of that variability will depend on the maternal side, as well.”

Single traits

The problem with EPDs, Taylor continues, is they are individual traits like birth weight, weaning weight or yearling weight.

“If producers select on a single trait, they could get themselves into big trouble by ignoring the other traits,” he said.

Taylor shared a story about a rancher who couldn’t sell his bulls because their birth weight was too high. He stopped feeding protein to his pregnant cows 30 days before they calved. It brought the birth weights and EPDs for birth weight down enough that he was able to sell the bull calves as easy calving bulls.

“There was no difference in genetics, it was strictly environmental effects,” he said.


Producers are responsible for reporting every calf that is born to the breed association, but they might not always do so. If 105-pound calf is born, the producer might make it into a steer.

“A lot of those bulls don’t get reported back to the breed,” he said.

Red Angus, Gelbvieh and Shorthorn have whole herd reporting systems, which requires producers to turn in records for every cow they have. Buyers have the advantage of information that is the result of more accurate reporting.

“Take a look at the association, their reporting rules and how things are reported back,” Taylor said.

“Some EPDs may be more accurate than others because of reporting requirements,” he said.

At many bull sales, buyers also have access to genomically enhanced EPDs to analyze for each bull. These EPDs were developed to enhance predictability and accuracy of EPDs for young, unproven bulls. Taylor said this technology can be used on young animals to help producers determine whether a bull calf should be a steer.

“It also helps producers analyze difficult to measure traits like feed efficiency, maternal and carcass traits,” he said. “It allows producers to identify sires with superior genetics a lot sooner.”

Gayle Smith is a correspondent for the Wyoming Livestock Roundup. Send comments on this article to

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